Cupcakes
by ShadowBest
Summary: Mumen Rider finds himself in a sticky situation. Somehow, he had gotten roped into baking cupcakes for a school's bake sale. When he finds the task too much to handle alone, who does he turn to for help? One-shot.


*** Implied Relationship.**

 *** This was a random thought so I decided to run with it. I literally thought of this just the night before, so tell me what you think.**

 *** Saitama/Genos pairing.**

 *** A bit more detail on them than I thought I'd go with.**

 *** Will contain a piece of worried-Mumen Rider.**

 *** I will be using the name Eiyuu for Mumen. For those who don't know, or remember, it's the name I gave him in Companionship.**

* * *

An insistent knock sounded, breaking Saitama's concentration from his manga. The man tried to ignore it, humming a little to block the sound. But the knocking just _wouldn't stop._ Finally, after the hero had read the same panel three times he snapped the paperback shut with a sigh. Heaving himself to his feet, the bald man scratched his ear idly, feet shuffling across the hardwood floor.

"Coming! Coming!" The man yelled eyebrows furrowing in irritation before he pulled the door open roughly. Mumen Rider stood in front of him, right arm raised and hand curled in a fist. His mousy, medium brown hair was mussed from the constant green, turtle-shell-like helmet held under his left arm. In a rare show, his goggles were pushed up, large, round glasses heavily obscuring, wide bright green eyes. Saitama huffed a little, any irritation he had felt before siphoning slowly away at the sight of the man.

"Saitama, hey." The guy sounded surprised, like he hadn't expected the bald hero answer. Even though this was _his_ apartment he had gone to. Saitama shook his head a little, brown eyes dull and a little flat. "Hey Eiyuu, come in." The bald hero bid entrance into the small space, stepping to press against the wall. "What brings you here?" Saitama asked curiously, mindlessly watching as the friendly man thanked him; slipping his shoes off as he stepped into the hallway.

The simple question brought a flush to the guy's face; cheeks tinging in a light pink as his glove-clad hand lifted to the back of his head. Saitama could only raise an eyebrow at the show; arms moving to cross over his chest as he studied the sheepish looking man. "Ah," The shy man started; green eyes moving to look at the floor left of where Saitama stood. "I kind of need a favor." Eiyuu mumbled; looking anywhere but at his bald friend. The hero hummed in response; hip cocking a little as he waited for the man to continue.

He's learned his lesson to agreeing to something without previous knowledge of it.

Unrelentingly steady eyes watched as the C-Class squirmed under the scrutiny; his face darkening as blood pooled inside of his cheeks. The sudden rush of color brought attention to the dimple on the left side of his mouth. "I-agreed-to-make-sweets-for-a-bake-sale-and-got-roped-into-making-a-thousand-cupcakes." The man's words came out in such a rush it was a wonder how his tongue didn't get tied in the process. It was only Saitama's heightened senses that allowed him to discern the mumbled explanation. Once his brain processed the meaning of his words; the man could only feel his eyes widen, arms slackening as his mind ground to a halt.

* * *

"A thousand cupcakes?" The man breathed; looking to his friend, desperately wishing that what he was told wasn't true. What the implications of the guy showing up on his doorstep meant. Mumen Rider could only nod; leather-covered fingers rubbing into the back of his neck still. The hero was more than happy to help civilians; it was his job to do so. He never had any reservations about doing something; not even when the threat was so much more than he could handle.

But the sheer amount and the time crunch he was put under overwhelmed the man. So, in desperation; the hero found himself dialing the number that he subconsciously thought of. He had never used it before; never had a reason to. Despite the physical trouble he found himself in constantly. Once the guy realized what he was doing; he scrambled to hang up, fingers fumbling with nerves. But, before he could even begin to close the flip phone; the steady, very intimidating voice of Demon Cyborg rang through the shoddy speaker.

"Hello," The S-Class hero had intoned. Mumen Rider had felt sweat bead at his forehead just from the greeting. Sure, he and Saitama were friends; he and Genos got along fine, but he hadn't found himself in this kind of situation before. "Hey, Genos." The hero found himself saying; his mind on autopilot as he began to pace in his apartment. "Mumen Rider." The cyborg had said in response; his voice perhaps a _smidge_ warmer than before; it was difficult to tell with him, let alone over the phone.

"How can I help you?" The teen asked; breaking the older male from his thoughts. Mumen Rider wasn't sure what he could say; but his mind went ahead anyway and he found himself explaining the situation. Barely aware of the little hums of understanding, the helpless man plopped down into his desk chair. The man found himself breathless; heart beating a little faster after he explained. He had started from the beginning; going so far to describe his patrol and ending to the predicament he got tangled in now.

"Of course, we can help, Mumen." Genos said; his six words lifting an immense weight off of the man's shoulders. "I'll just run to the market and pick up the ingredients if you'll bring the bakeware and head over to the apartment?" The cyborg said; yellow eyes glancing over to his distracted Sensei, not that the hero for justice knew this. Eiyuu found himself nodding along; a wide, relieved grin splitting his face. "I'll just take twenty-five minutes if you'll let Saitama know?" The hero breathed into the phone; scrambling around his moderate-sized abode to gather the supplies. "Yes, I'll let him know. I must be going; I can see the supermarket." The high-ranking hero said before ending the call.

* * *

Saitama groaned after Mumen Rider explained the events leading up until now. A pale, scarred hand rubbing over his face in an exasperated manner. Now that it was explained to him; there was a little niggle in his mind, bringing up the conversation that Genos had in fact had, warning the bald hero of this. The hero didn't want to do this; even though he had been warned, he still felt like he was roped into it. Saitama made the mistake of glancing towards his shorter friend. One look at the wide green eyes of a desperate hero had the other groaning.

Waving his hand quickly; like trying to swat a fly, the hero agreed. "Fine, fine, I'll do it." Despite the hero's discomfort to agreeing to this; he couldn't stop a small smile from briefly appearing at the sound of the other's happy cry. Before anything else could be said; the door pushed open, Genos' voice rushing into the apartment before the man himself. "Sensei, I'm ho-" The teen started; vision blocked by an armful of bags. The cyborg came in so quickly he didn't realize that they still stood practically in the doorway.

He was helpless to stop himself from tripping over Saitama's bare feet. The connection of metal feet meeting skin didn't register in the hero's mind; practically going unnoticed as the man moved automatically. One hand flashing out to catch the toppling bags; ingredients rustling in the confines and his other arm flashing out to grab the flailing teen. In a second; the cyborg jolted roughly, having been caught by the collar of his shirt. The man didn't have his air cut off from the snag, but it was still very uncomfortable. Before he could blink; Saitama pulled back again, the momentum with which he had fallen being used to pull the younger male into the elder's chest with an oomph.

Mumen Rider watched all of this with wide, shocked eyes. The situation happening so quickly that if he had blinked it would've gone unseen. The brown-haired hero could only gape slightly as he watched his friend move. Hands a mere blur as he rescued his disciple and the eggs and other ingredients from unceremoniously crashing to the floor. The bicycle-riding hero could only smile to himself as he saw Genos' shoulder plates open with a rush of steam, wide yellow eyes vibrant as he looked up to the bald hero.

Saitama looked as bored as ever; if not for the slight, amused smile on his lips. "Be more careful." He told his student before releasing the embarrassed teen. "Hey, King." Saitama greeted the dazed, scarred hero with a wave, gently pushing past Mumen to put the bags he was still holding in the kitchen. "Hey, man." The other hero greeted casually; despite the surprised expression he was wearing. The brown-haired man was jolted out of his silence by the sudden appearance of an extended hand.

"Hi, you must be Mumen Rider." King greeted him, mouth twitching upwards as Mumen looked to him in shock. "Genos told me about you, and the situation you've found yourself in." The S-Class hero said; mirth coloring his tone as he shook the other's hand. "H-hey." The lower-ranking hero stammered; glancing over to the still steaming, but less-flustered looking cyborg. "King has offered to help." Genos explained; finally noticing the eyes upon him. "Thanks." Mumen Rider said sincerely; green eyes brightening as he smiled in relief.

* * *

"Hey, are we gonna do this or what?" Saitama's voice rang through the kitchen to their ears. Each of them smiled to each other before moving into the suddenly cramped cooking space. It didn't help that the heat from the oven emanated freely in the small room. Saitama stood at the counter beside the stove; hips pressing into the edge as he stared intently at a recipe. Almost colored like his hero suit; the man stood wearing a pastel yellow apron.

Before anyone could comment on it; King and Mumen Rider were hit in the face with soft material, the color blocking their vision suddenly. "Put those on." Saitama said; not even looking at the pair before he flipped a page, leaning further over the book. "Why doesn't Genos get an apron?" King grumbled half-heartedly as he tied a pastel blue apron string around his waist. Mumen Rider was working on the green one he was offered; helmet and goggles left on the counter as he tied it into place. "Genos already has one." Saitama said; jerking his thumb over his shoulder as he began to pour flour into a measuring cup.

Both heroes turned to look in the direction where the hero gestured only to be met with an unexpected sight. Genos did indeed have his own apron. Already tied in place and with a matching bandana to cover his blonde hair was a bright pink apron. "What?" The teen asked; yellow eyes narrowing as he looked up to the surprised guests in front of him. "Why pink?" King was the one who managed to speak first; laughter barely concealed behind a trembling voice and twitching lips.

Genos sniffed in disdain as he straightened. "I like the color." He said simply; his voice so flat and serious that Mumen Rider couldn't stifle his laughter anymore. It wasn't everyday that one got to see Demon Cyborg go into what must've been **House-wife Mode** if with the practice he had turned and his hand switched from metal fingers to a pair of beaters one would find on an automatic mixer was anything to go by. After the pair of heroes calmed down from their laughing fit; they managed to settle enough to get to work. The quartet of heroes worked in near silence, occasionally asking one to pass something to another but otherwise they didn't interact much.

* * *

It had taken nearly ten minutes but they eventually found a rhythm with which to work by. King would gather ingredients and read from the book – after pushing Saitama away from it – Mumen Rider would get the dry and wet ingredients ready in their bowls. Genos took over mixing and portion-control, while Saitama would transfer the batches in and out of the oven. The first time Mumen Rider had seen the guy grab the hot tin without any protection, the surprised hero nearly shattered the ceramic bowls in his worry to check on the man. Saitama could only watch in confusion as his friend scrambled towards him; unblinking, he watched as the shorter hero held his hands, green eyes intently looking for any burn marks or forming blisters.

"Do your hands hurt?"

"No."

"There's no blisters?"

"Nope." He said; popping the 'p'.

The worried hero looked up to the other with narrowed eyes. "Be more careful." He scolded; cheeks tinging pink in embarrassment as he went back to his task. Resolutely not meeting the eyes of the others. From then on Saitama tried to remember to put an oven mitt on; if only to not worry his friend. But sometimes he forgot.

It wasn't like he could feel the burn that was supposed to be there. His skin had become resilient to sudden changes in temperature. But even after he explained this to the man the second time he forgot; he would 'tsk' each time the bald hero reached in with bare hands. Despite his obvious displeasure with how Saitama handled his task, he didn't say anything more on the matter after the third time around. Each hero was made to hear the displeased sound every time Saitama forgot the mitt.

* * *

The work had taken hours. The group of heroes were forced to work slower, lest they bump elbows the entire time. Too busy were they prepping that they couldn't enjoy the time between batches. Each man began to sweat as time went on; boxed in as they were. A companionable bond began to form between them as they moved on from baking to decorating.

The relief of being able to turn off the oven was palpable as they each armed themselves with a frosting pipe. The frosting was simple; two-toned in purple – food-colored vanilla – and white, which were the school colors. But despite the simplicity of the task; more than one hero found themselves on the end of another and ended up with colored frosting on his nose or cheek. Genos had ended up with a bit on his left cheek; King with a dab on his chin, Mumen Rider with a spot on his nose and Saitama with a portion smeared on his forehead. It was much like a movie reference; but the hero couldn't put his finger on which.

* * *

It was nighttime by the time they were done; stars sparkling in the sky as the heroes sluggishly said goodbye and parted ways. Each of them too tired to bother with clean-up. Rather than risk them being wrecked if they fell off the bike from his tired state, the group agreed to keep the sweets here for the night. After sending his two friends off; the bald hero sighed to himself. The smear of frosting dried and crusted on his forehead.

"Man, am I glad that's over." The hero moaned out; not unkindly. Genos hummed in agreement, kneeling beside their made futon as he ran through the last of his nightly check-ups. Saitama approached the teen; kneeling beside him as he let his hands wrap around his wrists. "You're a good friend, Genos." The older man said; leaning in and kissing the cyborg's forehead. "You're the good person, Sensei." The hero argued feebly; yellow eyes bright as his shoulders steamed in a sign of embarrassment.

Saitama didn't say anything; not bothering to argue about it. Instead, he stood again and went to wet a cloth with warm water. The bald hero stepped close to his partner once more; kneeling before the teen as he wiped gently at the dried frosting. Warm hands cupping the teen's face gently as he worked. He didn't protest as the cyborg pulled the cloth from him; cool, metal fingers pressing against his jaw softly as he gave him the same treatment.

After the teen pulled his hands away; the man caught his wrists in his hands, once more not allowing the other to go back to his nightly tasks. Genos looked up at him; head tilted back a little as Saitama settled in the man's lap, thankful more than ever how the cyborg preferred to sit in a seiza position. Even if the younger wanted to; he found himself helpless to stop the elder as the distance closed between them. Lips pressed together; moving together sweetly, the smell of cupcakes and frosting domineering their senses as tongues brushed against each other slowly. Genos couldn't stop the older man as he was pushed back against the futon; lips melded together still.

The pair remained tangled for an immeasurable amount of time. Cool and warm hands moving over flesh and metal. Somehow, without parting, they found themselves without shirts; bodies pressed flushed against the other. The pair soon fell apart after this; synthetic and real lips alike were puffy and wet, Saitama's head resting on Genos' chest as they drifted to sleep. Both of them forgetting to finish their regular routines as they found themselves caught up in the other's presence.

* * *

Sun streamed in through the window the next morning; the sound of insistent knocking waking the pair. Saitama groaned as he saw the time; arm throwing over his eyes to block out the light. Genos smirked to himself; leaning in and pressing a kiss to the man's forehead, metal fingers brushing over flexed muscle before the cyborg pulled himself from the warm, tangled sheets. The teen shuffled to the door; uncaring if he was without a shirt and that his hair remained a mess atop his head. "Hey, Genos." Mumen Rider's voice sounded as soon as the door pulled open.

"Sorry for visiting so early," The hero apologized; face tinging pink as he noted the bare chest of the cyborg. His eyes widening and face darkening as he could see Saitama's resting form on the one futon from the door. "I have to get the cupcakes." Mumen Rider explained his early presence; rubbing the back of his neck sheepishly as the teen nodded. The hero didn't have to wait long before the boxed cupcakes were pressed into his arms. Mumen Rider left soon after that; waving away the younger's offer to aid the hero.

He could see the glances the teen spared for his friend. The guy didn't want to leave his partner; much rather wanting to climb back into their bed. So, Mumen Rider shrugged and assured the hero that he would be able to handle the task. The man was hard pressed not to squirm under the other's scrutiny but relaxed when he had nodded. The bicyclist smiled as he waved to the cyborg before leaving.

Genos closed the door quietly behind the kind hero. A small smile on his face as he moved back into the shared living space. The teen wasted no time as he climbed under the sheets, sighing softly as he settled. "Who was that?" Saitama mumbled; voice filled with sleep as he pressed against the cyborg's side. "It was just Mumen." Genos said; hushing the man's inquiries as he pressed his lips to warm skin.

* * *

 **Disclaimer: I do not own One Punch Man or its Characters. The Author and One do.**

 **Author's Note: Hey, I hope you enjoyed the story. I would like to reassure everyone that I haven't forgotten about my stories. I am working on the next chapter for 'Companionship.' I'm just having trouble with it, so I decided to get this out of my system.**

 **Let me tell you, I wasn't sure about doing this. I didn't expect it to go in the direction it did. But I hope it was alright. This is my first Sai/Genos pairing, so be kind. Also, my first one-shot.**

 **I will be posting this on ao3 (Archiveofourown) under the same name; ShadowBest.**

 **Sorry if you guys thought the detail was lacking.**


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